LAS VEGAS (AP) — Nevada is suing the federal government in a bid to stop plans to ship plutonium cross-country next year from South Carolina to the nation's former nuclear proving ground north of Las Vegas.

In a statement Tuesday, outgoing Gov. Brian Sandoval and Attorney General Adam Laxalt repeated a vow that the state will fight "at every level" the U.S. Department of Energy plan to store radioactive bomb-making material at the

Nevada Nuclear Security Site.

Sandoval, a Republican, said Nevada won't stand for the threat that shipping and storing highly toxic and cancer-causing material could pose to public health and safety.

State officials worry that an accident could permanently harm a Las Vegas area home to 2.2 million permanent residents and host to more than 40 million tourists a year.

The lawsuit, filed Friday in U.S. District Court in Reno, accuses the Energy Department of failing to properly study environmental threats posed by moving about 2,200 pounds (1 metric ton) of weapons-grade plutonium from the federal Savannah River nuclear weapons refining complex in South Carolina to Nevada by New Year's Day 2020.

The plutonium has been designated for national security use and is not waste, National Nuclear Security Administration and Energy Department spokesman Gregory Wolf said in a statement that noted the government is responding to a deadline set by a federal judge in South Carolina.

The material will be "temporarily staged" at the Nevada National Security Site and the government's Pantex Plant in Texas, two facilities that already handle and process plutonium, before eventually being sent to the Los Alamos National Laboratory in New Mexico "or another facility," the statement said.

"Because this is now a matter in litigation, NNSA will be unable to respond to questions or provide further information," it said.

In a final letter to Sandoval on Nov. 20, the Energy Department said it expects to move the material from Nevada to New Mexico "by the 2026-2027 timeframe," according to the lawsuit. The court filing accused federal officials of providing "none of the assurances Nevada requested."

Robert Halstead, head of the Nevada Agency for Nuclear Projects and the top state official fighting the proposal, expressed concern the material would end up permanently stored less than 100 miles from Las Vegas, and said he wasn't sure shipment hadn't already begun.

The Energy Department is on the hook to move 34 metric tons (nearly 75,000 pounds) of material, Halstead said. He expressed concern that after the first truckloads make the nearly 3,200-miles (5,150-kilometers) trip to Nevada, hundreds more would follow.

"We need to know for transportation safety purposes exactly what will be in those 10 truckloads," he said Tuesday. "I hope they have not already brought a shipment here."

The facility designated to accept the plutonium shipments is a vast federal reservation near, but separate from, the Yucca Mountain site that Nevada's congressional delegation and governors have long fought to prevent from becoming the repository for the nation's spent nuclear fuel.

Some members of Congress want to restart the mothballed Yucca Mountain project to accept and entomb radioactive material currently stored at power plants in 39 states.